src/unix/evtloopunix.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/unix/evtloopunix.cpp
   3 // Purpose:     wxEventLoop implementation
   4 // Author:      Lukasz Michalski (lm@zork.pl)
   5 // Created:     2007-05-07
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2006 Zork Lukasz Michalski
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ===========================================================================
  12 // declarations
  13 // ===========================================================================
  14
  15 // ---------------------------------------------------------------------------
  16 // headers
  17 // ---------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #if wxUSE_CONSOLE_EVENTLOOP
  23
  24 #include "wx/evtloop.h"
  25
  26 #ifndef WX_PRECOMP
  27     #include "wx/app.h"
  28     #include "wx/log.h"
  29 #endif
  30
  31 #include <errno.h>
  32 #include "wx/apptrait.h"
  33 #include "wx/thread.h"
  34 #include "wx/module.h"
  35 #include "wx/unix/pipe.h"
  36 #include "wx/unix/private/timer.h"
  37 #include "wx/unix/private/epolldispatcher.h"
  38 #include "wx/private/selectdispatcher.h"
  39
  40 #define TRACE_EVENTS _T("events")
  41
  42 // ===========================================================================
  43 // wxEventLoop::PipeIOHandler implementation
  44 // ===========================================================================
  45
  46 namespace wxPrivate
  47 {
  48
  49 // pipe used for wake up messages: when a child thread wants to wake up
  50 // the event loop in the main thread it writes to this pipe
  51 class PipeIOHandler : public wxFDIOHandler
  52 {
  53 public:
  54     // default ctor does nothing, call Create() to really initialize the
  55     // object
  56     PipeIOHandler() { }
  57
  58     bool Create();
  59
  60     // this method can be, and normally is, called from another thread
  61     void WakeUp();
  62
  63     int GetReadFd() { return m_pipe[wxPipe::Read]; }
  64
  65     // implement wxFDIOHandler pure virtual methods
  66     virtual void OnReadWaiting();
  67     virtual void OnWriteWaiting() { }
  68     virtual void OnExceptionWaiting() { }
  69
  70 private:
  71     wxPipe m_pipe;
  72 };
  73
  74 // ----------------------------------------------------------------------------
  75 // initialization
  76 // ----------------------------------------------------------------------------
  77
  78 bool PipeIOHandler::Create()
  79 {
  80     if ( !m_pipe.Create() )
  81     {
  82         wxLogError(_("Failed to create wake up pipe used by event loop."));
  83         return false;
  84     }
  85
  86     const int fdRead = GetReadFd();
  87
  88     int flags = fcntl(fdRead, F_GETFL, 0);
  89     if ( flags == -1 || fcntl(fdRead, F_SETFL, flags | O_NONBLOCK) == -1 )
  90     {
  91         wxLogSysError(_("Failed to switch wake up pipe to non-blocking mode"));
  92         return false;
  93     }
  94
  95     wxLogTrace(TRACE_EVENTS, wxT("Wake up pipe (%d, %d) created"),
  96                fdRead, m_pipe[wxPipe::Write]);
  97
  98     return true;
  99 }
 100
 101 // ----------------------------------------------------------------------------
 102 // wakeup handling
 103 // ----------------------------------------------------------------------------
 104
 105 void PipeIOHandler::WakeUp()
 106 {
 107     if ( write(m_pipe[wxPipe::Write], "s", 1) != 1 )
 108     {
 109         // don't use wxLog here, we can be in another thread and this could
 110         // result in dead locks
 111         perror("write(wake up pipe)");
 112     }
 113 }
 114
 115 void PipeIOHandler::OnReadWaiting()
 116 {
 117     // got wakeup from child thread: read all data available in pipe just to
 118     // make it empty (even though we write one byte at a time from WakeUp(),
 119     // it could have been called several times)
 120     char buf[4];
 121     for ( ;; )
 122     {
 123         const int size = read(GetReadFd(), buf, WXSIZEOF(buf));
 124
 125         if ( size == 0 || (size == -1 && (errno == EAGAIN || errno == EINTR)) )
 126         {
 127             // nothing left in the pipe (EAGAIN is expected for an FD with
 128             // O_NONBLOCK)
 129             break;
 130         }
 131
 132         if ( size == -1 )
 133         {
 134             wxLogSysError(_("Failed to read from wake-up pipe"));
 135
 136             break;
 137         }
 138     }
 139
 140     // writing to the wake up pipe will make wxConsoleEventLoop return from
 141     // wxFDIODispatcher::Dispatch() it might be currently blocking in, nothing
 142     // else needs to be done
 143 }
 144
 145 } // namespace wxPrivate
 146
 147 // ===========================================================================
 148 // wxEventLoop implementation
 149 // ===========================================================================
 150
 151 //-----------------------------------------------------------------------------
 152 // initialization
 153 //-----------------------------------------------------------------------------
 154
 155 wxConsoleEventLoop::wxConsoleEventLoop()
 156 {
 157     m_wakeupPipe = new wxPrivate::PipeIOHandler();
 158     if ( !m_wakeupPipe->Create() )
 159     {
 160         wxDELETE(m_wakeupPipe);
 161         m_dispatcher = NULL;
 162         return;
 163     }
 164
 165     m_dispatcher = wxFDIODispatcher::Get();
 166     if ( !m_dispatcher )
 167         return;
 168
 169     m_dispatcher->RegisterFD
 170                   (
 171                     m_wakeupPipe->GetReadFd(),
 172                     m_wakeupPipe,
 173                     wxFDIO_INPUT
 174                   );
 175 }
 176
 177 wxConsoleEventLoop::~wxConsoleEventLoop()
 178 {
 179     delete m_wakeupPipe;
 180 }
 181
 182 //-----------------------------------------------------------------------------
 183 // events dispatch and loop handling
 184 //-----------------------------------------------------------------------------
 185
 186 bool wxConsoleEventLoop::Pending() const
 187 {
 188     if ( m_dispatcher->HasPending() )
 189         return true;
 190
 191 #if wxUSE_TIMER
 192     wxUsecClock_t nextTimer;
 193     if ( wxTimerScheduler::Get().GetNext(&nextTimer) &&
 194             !wxMilliClockToLong(nextTimer) )
 195         return true;
 196 #endif // wxUSE_TIMER
 197
 198     return false;
 199 }
 200
 201 bool wxConsoleEventLoop::Dispatch()
 202 {
 203     DispatchTimeout(static_cast<unsigned long>(
 204         wxFDIODispatcher::TIMEOUT_INFINITE));
 205
 206     return true;
 207 }
 208
 209 int wxConsoleEventLoop::DispatchTimeout(unsigned long timeout)
 210 {
 211 #if wxUSE_TIMER
 212     // check if we need to decrease the timeout to account for a timer
 213     wxUsecClock_t nextTimer;
 214     if ( wxTimerScheduler::Get().GetNext(&nextTimer) )
 215     {
 216         unsigned long timeUntilNextTimer = wxMilliClockToLong(nextTimer / 1000);
 217         if ( timeUntilNextTimer < timeout )
 218             timeout = timeUntilNextTimer;
 219     }
 220 #endif // wxUSE_TIMER
 221
 222     bool hadEvent = m_dispatcher->Dispatch(timeout) > 0;
 223
 224 #if wxUSE_TIMER
 225     if ( wxTimerScheduler::Get().NotifyExpired() )
 226         hadEvent = true;
 227 #endif // wxUSE_TIMER
 228
 229     return hadEvent ? 1 : -1;
 230 }
 231
 232 void wxConsoleEventLoop::WakeUp()
 233 {
 234     m_wakeupPipe->WakeUp();
 235 }
 236
 237 void wxConsoleEventLoop::OnNextIteration()
 238 {
 239     // call the signal handlers for any signals we caught recently
 240     wxTheApp->CheckSignal();
 241 }
 242
 243
 244 wxEventLoopBase *wxConsoleAppTraits::CreateEventLoop()
 245 {
 246     return new wxEventLoop();
 247 }
 248
 249 #endif // wxUSE_CONSOLE_EVENTLOOP